1Institute of Applied Ecology Chinese Academy of Sciences, Shenyang 110 016, China.
2College of Agronomy, South China Agricultural University, Guangzhou 510 642, China.
*Correspondence author: E-mail: kongch@iae.ac.cn
The development of rice allelopathy is to lessen reliance on herbicides and reduce labour input in paddy ecosystems. The varietal improvement in rice allelopathy is an essential prerequisite for the practical application of paddy weed control. In this study, allelopathic rice PI312777 was hybridized with non-allelopathic modern rice cultivars N28S, N9S, N2S, N13S, Peiai64S and Tehuazhan35 in South China. Weed suppression and allelopathic index of these seven parents and their progeny plants were investigated in field and laboratory. Crosses between allelopathic and nonallelopathic rice varieties showed that allelopathic traits are quantitatively inherited and inheritance pattern of allelopathy in rice showed polymorphism in allelic interactions. Particularly, allelopathic traits of N2S/PI312777 progeny plants were enhanced greatly and there was positively-significant heterotic effect between allelopathic PI312777 and non-allelopathic N2S. Three rice lines of high grain yields and potent weed suppression in F8 derived from the crosses among those of N2S and PI312777 were selected as candidates for commercially acceptable allelopathic rice cultivars. These three allelopathic rice lines greatly reduced the emergence and growth of paddy weeds, besides no grain yield reduction occurred than control. Allelopathic rice No 1, a commercially acceptable allelopathic rice cultivar, is developing in Guangdong Province, China.
Allelopathy, Oryza sativa L, paddy weed management, traditional breeding, varietal improvement
